Barring him being good or bad, Tahm Kench is just not fun to play.

I mean lets be real, he's too immobile to really go offensive. No one is just going to let you get 3 stacks of your passive and get eaten, which actually isn't even as good as a regular stun because you can't damage the enemy while they're eaten and you're completely immobile. You're pretty much relegated to being the Uber driver on your team once per FOREVER because the cooldown on his ult is insanely long and occasionally eating a squishy team mate and running away.

He's like an even MORE defensive Braum. And for all intents and purposes Braum is better for the most part outside of situational mobility. Braum can apply his passive and stun in 3 hits, Tahm has to get 3 hits and then hit with an ability to get the stun AND his teammates can't help out, where as braum's can. Braum can dash to teammates that are in trouble where as Kench has to be in the right spot at the right time to eat someone. Braum can NEGATE projectiles and damage, Tahm just soaks it. And not to mention Braum has an AOE knockup / slow where as Tahm has no real AOE teamfight utility. Not to mention the fact that Tahm's passive isn't even REALLY a passive, its just there as part of his other 2 abilities.

So yeah. More boring, worse Braum. Unless his team up ganks with his ult are really good I don't expect to see much of him in high level play unless its to counter certain champs like Zed.